1. Field of the Invention
The present invention relates to a connection structure between a resolver and a lead wire.
2. Background of the Related Art
A resolver is usually used in a brushless motor in order to detect a rotational position of a rotor magnet arranged in the brushless motor. The resolver includes a resolver stator having at an inner circumference thereof a plurality of teeth, and a resolver rotor arranged radially inwardly of the resolver stator. The resolver rotor arranged in a concentric manner with the rotor magnet rotates with the rotor magnet in a uniform manner.
An excitation winding or an output winding is wound around each tooth. When the resolver rotor rotates, its radial gap formed between the resolver stator will be modified causing a voltage generated by the output winding to be changed. The resolver detects the change in the voltage so as to detect the rotary portion of the rotor magnet within the brushless motor.
The excitation winding or the output winding wound around each tooth is connected to one end of a terminal member arranged at the resolver stator. The lead wire is connected to the other end of the terminal member. The lead wire connects an external control device and the resolver.
As described above, the lead wire is connected to the terminal member of the resolver. This connection, however, may be broken when a motor including such resolver is included in an automobile, or the like, which may be vibrated or shaken. That is, the lead wire, in particular the connection thereof with the terminal member, may be damaged due to an external force.
Needless to say, reliability is required of the connection between the terminal member and the lead wire. Also, it is required that the resolver be small in size due to a limited space in which the resolver will be arranged. That is, it is important that the resolver is designed to be small in size while providing a secure connection with the lead wire.
Conventionally, a resolver has been available in which, in order to have a reduced radial size, a terminal pin thereof and a lead wire extend in a direction along a rotational axis. However, the lead wire in such resolver will be guided in a circumferential direction and then guided in an axial direction of the stator. Therefore, when an external force in the circumferential direction is applied to the lead wire, the force may be conducted to a portion connecting the lead wire with the resolver.
In order to connect the lead wire to the resolver, a method in which a separate component is arranged therebetween has been available. However, this method will increase a production cost.